Data storage devices generally operate to store and/or retrieve data in a fast and efficient manner. Some storage devices utilize a rotatable storage medium which is accessed by a radially moveable transducer to carry out data transfer operations with tracks defined on the medium.
The transducer is often supported by an actuator positioned adjacent an outermost circumference of the medium. Different forms of actuators are known, including linear actuators and pivot (rotary) actuators. The media can store the data in a variety of forms, such as optically (e.g., optical discs), magnetically (e.g., hard disc drives), etc. The media can be pre-recorded or recordable (either once or many times).
The configuration of the various tracks on a media surface is usually determined during media or device manufacturing. The tracks can be defined as a series of discrete concentric rings, or as a continuous spiral that extends across the radius of the medium. Depending on the construction of the medium, multiple recording layers may be employed to further increase the data storage capacity of the medium. Usually, both user data content and overhead servo data will be intermittently stored along each track. The user data content (e.g., programming, video, audio, etc.) is output to a host device, whereas the servo data provides closed loop tracking information to a servo system used to position the data transducer.
Track width refers to the overall radial width of the information stored along a given track. Track pitch refers to the radial distance from the center of one track to the next track. It can be seen that track width is related to track pitch. These values will be identical if there is no intervening buffer space between adjacent tracks. Historically, storage media were often provided with consistent track widths (and consistent track pitches); that is, the track width/pitch did not vary across the medium surface, but rather were maintained substantially constant.